The increased use of smartphones and other mobile devices using internet applications, video calls and e-mail is driving an unprecedented increase in world-wide wireless network traffic.
From a Network operator's perspective, the key factors in driving wireless network topologies are their ability to meet demands for bandwidth, user capabilities as well as quality of service, QoS.
Achieving the required capacities and fulfilling the quality of service, QoS, requirements depend on multiple factors, such as proximity of the users relative to the base station of the transceivers, the numbers of users in a cell, data throughputs and patterns as well as core network capabilities.
In conventional cellular networks macrosites can be installed on e.g. roof tops or at designated cell sites that typically have the base band units with the transceivers and RF power amplifiers in a cabinet enclosure while the antenna resides for instance on a tower mast. In such a conventional network the cabinet can be connected using a coaxial cable to the antenna on the antenna mast. This is the most common cell site approach for mobile cellular networks.
In LTE networks, the network architecture is transformed by the introduction of remote radio heads, RRH, which can be connected to a base station BS via fiber optic cables. The network can employ macro or micro base stations, the same as a traditional cellular site, but instead of having a conventional tall antenna mast, fiber optic cables can be used to distribute the base station signals for a group of antennas placed remotely in outdoor or indoor locations where required.
A common public radio interface, CPRI, forms a protocol interface between a radio equipment control, REC, and a radio equipment, RE, in a wireless network. The station is in a conventional wireless network located adjacent to the antenna in a small cabinet at the base of the antenna tower. Finding suitable sites can be a challenge because of the footprint required for the cabinet, a possible need for structural reinforcement of roof tops as well the availability of primary and back-up power sources. The common public radio interface, CPRI interface, allows the use of a distributed architecture where base stations containing the radio equipment control REC can be connected to remote radio heads RRH via wireless fiber links that carry the CPRI data. This architecture makes it possible that the remote radio heads RRH containing the radio equipment RE can be situated in environmentally challenging locations. The base stations containing the radio equipment control REC can be located centrally in less challenging locations where footprint, climate and power availability can be managed more easily. The CPRI data is transmitted in a downlink DL by the base station to the radio equipment RE and received in an uplink UL by the base station from the radio equipment RE.
According to the CPRI protocol, there are two links, i.e. the uplink UL and the downlink DL which are always running, i.e. the receiving and transmitting data transmissions exist all the time. The time division duplex, TDD protocol, is emulated by the CPRI protocol as a transmission perception of zeroes via a link. The CPRI link comprises an uplink UL for receiving CPRI data from said radio equipment RE and said downlink DL for transmitting CPRI data to said radio equipment RE, wherein a zero bit stream it is transported in the uplink UL, when CPRI data is transported in the downlink DL, and wherein a zero bit stream is transported in the downlink DL, when CPRI data is transported in the uplink UL.
If the uplink/downlink ratio UL/DL-ratio is, for instance, 0.5 then. 50% of the bandwidth BW is wasted. The CPRI framer, the CPRI direct memory access DMA, controller of a conventional CPRI lane controller transfers zeroes to the link in the quiet periods so that the required traffic with the memory connected to the CPRI lane controllers is double the really necessary required traffic carrying information.
Consequently there is a bandwidth, BW, waste in the internal system bus of the processor which comprises a conventional common public radio interface, CPRI, lane controller.
Accordingly, it is an object of the present invention to provide a common public radio interface, CPRI, lane controller that overcomes the above-mentioned problems and which avoids an unnecessary occupation of bandwidth BW in an internal system bus of the respective processor.